Large-scale urban underground hydro-thermal modelling - A case study of the Royal Borough of Kensington and Chelsea, London

Asal Bidarmaghz; Ruchi Choudhary; Kenichi Soga; Ricky L Terrington; Holger Kessler; Stephen Thorpe

doi:10.1016/j.scitotenv.2019.134955

Large-scale urban underground hydro-thermal modelling - A case study of the Royal Borough of Kensington and Chelsea, London

Sci Total Environ. 2020 Jan 15:700:134955. doi: 10.1016/j.scitotenv.2019.134955. Epub 2019 Oct 31.

Authors

Asal Bidarmaghz¹, Ruchi Choudhary², Kenichi Soga³, Ricky L Terrington⁴, Holger Kessler⁴, Stephen Thorpe⁴

Affiliations

¹ School of Civil and Environmental Engineering, University of New South Wales, Sydney, Australia; Department of Engineering, University of Cambridge, Trumpington Street, CB2 1PZ, UK. Electronic address: a.bidarmaghz@unsw.edu.au.
² Department of Engineering, University of Cambridge, Trumpington Street, CB2 1PZ, UK; Data-centric Engineering, Alan Turing Institute, UK.
³ Department of Civil and Environmental Engineering, University of California, Berkeley, USA.
⁴ British Geological Survey, Keyworth, Nottingham NG12 5GG, UK.

PMID: 31739273
DOI: 10.1016/j.scitotenv.2019.134955

Abstract

The shallow subsurface of dense cities is increasingly exploited for various purposes due to the significant rise in urban populations. Past research has shown that underground activities have a significant impact on local subsurface temperatures. However, the resulting spatial variability of ground temperature elevations on a city-scale is not well understood due to the lack of sufficient information and modelling complexity at such large scales. Resilient and sustainable planning of underground developments and geothermal exploitation in the short and long-term necessitate more detailed, more reliable knowledge of subsurface thermal status. This paper investigates the impact of some common underground heat sources such as train tunnels and residential basements on subsurface temperature elevation on a large scale and highlights the influence of local geology, hydrogeology, density, and type and arrangement of the heat sources on ground thermal disturbance. To tackle the size issues and computational expenses of such a large-scale problem, a semi-3D hydro-thermal numerical approach is presented to capture the combined influence of underground built environment characteristics coupled with ground properties on ground temperature elevation within the Royals Borough of Kensington and Chelsea (RBKC), London. Numerical results show that the extent of ground thermal disturbance is mostly affected by geological and hydrogeological characteristics in permeable ground (River Terrace Deposits). Density and spatial distribution of heat sources, however, are critical parameters in ground temperature evaluation in highly impermeable ground such as London Clay Formation. The locality of temperature rise and potential ground energy within immediate impermeable ground surrounding heat sources versus significantly large extent of ground thermal disturbance in permeable ground, highlights the significant dependency of ground thermal state and geothermal potential at the studied site to the ground and underground built environment characteristics and necessitates a better understanding of shallow subsurface thermal state for a sustainable and resilient urban underground development.

Keywords: Geology; Geothermal energy; Groundwater; Large-scale urban modelling; Subsurface temperature; Underground structures.